Illustrated herein are embodiments relating to a method and apparatus for insulating printer/copier printheads. It finds particular application in conjunction with an imaging apparatus having solid ink printheads, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Image producing machines, such as printers and/or copiers and the like, often use printheads for ejecting ink onto an ink receiving surface, such as print media also referred to as the substrate, or an image drum which is then transferred to the print media, to form an image thereon. Solid ink image producing machines use solid ink, also referred to as phase change ink. The solid ink is in the solid phase at ambient temperature and is melted to a molten, liquid phase at an elevated, operating temperature. At the operating temperature, droplets or jets of the molten liquid ink are ejected from one or more printheads to form the image. When the ink droplets contact the surface of the substrate, they quickly solidify to create an image in the form of a predetermined pattern of solidified ink drops.
Solid ink printheads require a significant amount of energy to melt the ink and keep it in the liquid phase so that it can be ejected onto the receiving surface. However, oftentimes the device is not used continuously and it may sit idle for a significant percentage of time it is turned on. As a result, solid ink imaging devices can consume power even while sitting idle.
Today however, energy conservation is popular. Reducing the energy consumed by devices, including imaging devices, conserves natural resources and saves the owner/operator money thereby providing a valuable feature which can make the device more marketable. Many imaging devices have a low energy mode, also referred to as a sleep mode, when sitting idle for a period of time. One way to reduce the energy consumption of solid ink imaging devices is to turn off the power being used to heat the printheads while in the low energy mode. This option is not desirable because it results in thermal cycling failures at the piezo electric bonds in the heating elements used to heat the ink. It also results in significant ink usage to clear the printheads of air bubbles formed during the cool down cycle when the ink solidifies. Further it inconveniences the user with longer startup times when the machine is operated after sitting idle.
Another option to keep energy consumption low is to insulate the printheads and supply just enough power to keep the ink molten during the low energy mode. Applying thermal insulation to as many of the printhead external surfaces as possible helps to minimize the amount of energy required to maintain the ink temperature above its melting point. Insulating the front face of the printhead, however, is quite challenging because it contains the apertures through which ink is jetted onto the receiving surface and therefore, the front face of the printhead needs to be exposed to the receiving surface during normal operation. Further, the printhead front face is typically disposed in close proximity to the receiving surface when forming the image. It is desirable to solve these problems in order to reduce the energy consumed by the solid ink imaging device.